ARM Cortex-M3 Technical Reference Manual page 235

ARM DDI 0337B
Table 11-17 Settings for DWT Function Registers (continued)
Value Function
b0101 Watchpoint on read.
b0110 Watchpoint on write.
b0111 Watchpoint on read or write.
b1000 ETM trigger on PC match
b1001 ETM trigger on read
b1010 ETM trigger on write
b1011 ETM trigger on read or write
b1100 Reserved
b1101 Reserved
b1110 Reserved
b1111 Reserved
Note
• If the ETM is not fitted, then ETM trigger is not possible.
• Data value is only sampled for accesses which do not fault (MPU or bus fault).
The PC is sampled irrespective of any faults. The PC is only sampled for the first
address of a burst.
• PC match is not recommended for watchpoints because it stops after the
instruction - it is mainly used for guards and for ETM triggering.
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System Debug
11-25